Requires 3+ mm of base spacing to clear exhaust at BDC and decking or counter-sunk head to get the squish back in spec, resulting in some extreme port timing. Rings need gapping. Wrist pin clips are made from paper clips, replaced with malossi units. Replaced steel reeds with carbon for safety. Details here: http://www.mopedarmy.com/forums/read.php?7,3839377